INSECT PESTS OF OHIO SHADE AND FOREST TREES 169 



blackened or badly dried roots, or those showing- any symptoms of 

 disease or insect attack should be discarded. To accept job lots 

 of stock because it is cheap is never economy, for the first cost of 

 the tree is one of the smallest items. In the production of a 

 splendid tree, time is the greatest item of expense, and anything 

 within reason to be done by way of securing the rapid development 

 of desirable species is well worth while. 



Plant to allow an opportunity for development. — Frequently 

 the site of planting is such that tree growth is almost impossible. 

 The soil msiy be unadapted to its needs because of chemical com- 

 position or physical condition or texture — indeed, in many instances 

 trees are planted in such cramped situations that there actually 

 does not exist a sufficient quantity of soil, regardless of its quality, 

 for their development. Roughly speaking, the unhampered roots 

 of a tree extend laterally as far as the branches; hence it is little 

 wonder that trees fail to thrive when supplied with a narrow strip 

 of surface earth from 1 to 2 feet in width, the remainder of the 

 area being covered with sidewalk and paving. In many towns and 

 cities in Ohio one can scarcely find a street where the area, between 

 the sidewalk and paving, allotted to trees is more than 2 feet in 

 width and, as might be expected, rarely is a beautiful tree to be 

 seen in such places. In addition to the handicap of a narrow tree 

 belt, the trees are frequently set too thick in the row. (Note for 

 example Plate I, Fig. 1.) The wonder is not that the trees present 

 a shaggy, sickly aspect, but that any trees exist to present any 

 aspect at all. 



On the other hand, well-selected stock planted in a tree belt of 

 generous width will thrive under city conditions, and with care 

 may surmount the difficulties attending a city environment. (See 

 Plate I, Fig. 2.) 



Avoid planting large areas to a single species. — Another factor 

 which may be mentioned as being associated with that of insect 

 control is the correct grouping or distribution of the various species 

 of trees. The theory is supported by abundant available evidence 

 that it is unwise to devote large areas to a single species, as is so 

 frequently done. Occasionally, practically entire towns are found 

 in Ohio which present almost a pure stand of a single species, and 

 not infrequenfly are found entire sections so planted. 



From the esthetic standpoint such uniformity is highly com- 

 mendable but from the practical standpoint of insect control, it is 

 to be avoided. The danger in planting large areas to a given 

 species lies in the fact that most insects prefer certain food plants ; 



